M.C. Rao, K. Ravindranadh, T. Srikumar, G.V. Ramana, K.L. Sirisha, T. Rosemary, M. David Raju, M. Manoranjani and G. Nagarjuna

ABSTRACT

SnO2 is a special oxide material because it has a low electrical resistance with high optical transparency in the visible range. SnO2 sensor is invariably anion deficient and oxygen vacancies are mainly responsible for making available free electrons for the conduction process. Cu2+ doped SnO2 thin films were prepared by using chemical spray pyrolysis method. The prepared thin films were characterized by FTIR, electrical, gas sensing and thermo emf. The bands at the low wave numbers 500-1000 cm?1 could be attributed to SnO2. The peaks at 677, 786 and 965 cm?1 were assigned to O–Sn–O, Sn–O–Sn stretching vibrations and lattice vibrations, while the peaks at 569 and 864 cm?1 were due to Sn–OH bonds of the SnO2 crystalline phase. The thermo emf of Cu2+ doped SnO2 thin films increased with the increasing of temperature. At low temperatures the Seebeck coefficient is observed to be high and the Seebeck coefficient decreases with increasing of temperature. The large values of thermoelectric power of Cu2+ doped SnO2 thin films are typical of semiconductor behavior. Keywords: SnO2, Thin films, Spray pyrolysis, FTIR, Thermo emf, Gas Sensing and Electrical.